The problem was really that the panel was put together too well. We were counting on that the leather was stretched over the aluminum panel, and that we could stretch and move it while we were cutting the panel. But everything was glued fully, which limited our cutting and grinding range.

This time of year we always struggle to get some wheels off. Last year we had to get the big impact wrench come specially for one overtightened lug nut. Now I have two again that I cannot get off by myself, even with an eight feet cheater pipe. I don't like the extreme bruto force of the cheater bar and I am always concerned to break the breaker bar

I was reading about these torque multipliers and it sounds like they work very well. Also, since you've done this before you probably already know this, but one of the articles I read said that during reassembly, it is really important to grease the inside of the rim that the center nut rests against, in addition to the threads of the center nut and spindle.